Add agent server management functions

[pan-x-c]

Description

Add a series of agent server management functions, and extract management related functions from the original call_func interface. All agent server management functions are listed below:

• is_alive
• create_agent
• delete_agent
• clone_agent
• get_agent_id_list
• get_agent_info
• get_server_info

Checklist

Please check the following items before code is ready to be reviewed.

• [x] Code has passed all tests
• [x] Docstrings have been added/updated in Google Style
• [x] Documentation has been updated
• [x] Code is ready for review